This invention relates to a dome switch for an electrically operated product.
Dome switches have previously included an electrically conductive switch member of a domed shape that is mounted on a circuit board of an electrically operated product either by fixed mounting connections or by an adhesive tape. During flattening actuation of the dome switch member to electrically connect two or more contacts on the circuit board, the fixed mounting connections are stretched in a manner than can eventually cause detachment and misalignment with the contacts. Likewise, the adhesive tape can also detach and permit misalignment.
Patents noted during an investigation conducted in connection with this invention include U.S. Pat. No. 4,289,942 Milianowicz; U.S. Pat. No. 4,319,099 Asher; U.S. Pat. No. 4,349,712 Michalski; U.S. Pat. No. 4,595,809 Pool; U.S. Pat. No. 4,933,522 Celander; U.S. Pat. No. 4,978,818 Rothlin; U.S. Pat. No. 5,399,823 McCusker; U.S. Pat. No. 5,595,288 Matsui et al.; U.S. Pat. No. 5,898,147 Domzalski et al; and U.S. Pat. No. 5,986,228 Okamoto et al.
An object of the present invention is to provide an improved dome switch for an electrically operated product.
In carrying out the above object, the improved dome switch of the invention is utilized with an electrically operated product having a housing and a circuit board mounted by the housing. First and second electrical contacts are mounted on the circuit board in a spaced relationship from each other. An electrically conductive dome switch member of the dome switch has a domed shape with a central portion including a dimple that projects toward but is normally spaced from the first contact on the circuit board. The dome switch member has a peripheral portion that is slidably engaged with the second contact. Two retainers of the dome switch retain the dome switch member on the circuit board but permit sliding alignment therebetween. A switch actuator of the dome switch is actuatable to flatten the dome switch member and move the dimple of its central portion into contact with the first contact and thereby electrically connect the first and second contacts. The switch actuator has an alignment button that is received by the dimple in the central portion of the dome switch member to provide sliding thereof on the circuit board and alignment with the first and second contacts upon its initial flattening actuation by the switch actuator.
The dome switch of the invention as described above thus overcomes unreliable operation of prior art dome switches by allowing the dome switch member to essentially float and self aligned with the contacts on the circuit board during the flattening actuation.
In one construction, the two retainers extend between the circuit board and the housing to retain the dome switch member while permitting sliding thereof on the circuit board to provide the alignment with the first and second contacts.
In another construction, the two retainers extend from the circuit board over the periphery of the dome switch member to retain the dome switch member while permitting sliding thereof on the circuit board to provide alignment with the first and second contacts.
Certain embodiments disclosed each have the periphery of the dome switch member including a pair of first legs retained by the two retainers and also including a second pair of legs that slidably engage the circuit board with one of the second pair of legs providing the slidable engagement of the dome switch member periphery with the second contact.
Different embodiments have the dome switch member provided with a generally star shape which is disclosed as having four legs, a generally cross shape including four legs that slidably engage the circuit board, a generally round shape having a round periphery that slidably engages the circuit board, and a rectangular shape that may be square or elongated.
The objects, features and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.